1. Clinic of Plastic, Reconstructive, Hand and Burn Surgery, Cologne-Merheim Hospital, Witten/Herdecke University, 51109 Cologne, Germany
2. Department of Plastic Surgery and Hand Surgery, Gemeinschaftskrankenhaus Havelhoehe, Teaching Hospital of the Charité Berlin, Kladower Damm 221, 14089 Berlin, Germany
3. Clinic of Plastic Surgery, University Hospital Aachen, Pauwelsstraße 30, 52074 Aachen, Germany
4. Institute for Research in Operative Medicine (IFOM), Cologne-Merheim Hospital, Witten/Herdecke University, Ostmerheimer Str. 200, 51109 Cologne, Germany